Had a four speed box that grumbled and groaned itself into an early (25 years) grave.

Picked up a 5 speed box entirely by accident, but the garage bolted it in and I can get all gears (honest) with nothing else changed or modified.
BUT>> its a little clunkier than my other five speed from factory. So, is there sommat different under the gear stick? I am guessing its in that silver box above the spare wheel...And what do I need to change?
thanks
Em
x